An isosceles triangle has side lengths 8 cm, 8 cm and 10 cm.  The longest side of a similar triangle is 25 cm. What is the perimeter of the larger triangle, in centimeters?
The ratio of the length of the longest sides of the small triangle to the large triangle is $10/25 = 2/5$, which must hold constant for all sides of the two triangles since they are similar.  Thus the perimeters of the two triangles are also in the ratio of $2/5$.  The small triangle has perimeter $8+8+10=26$, so the large triangle has perimeter $\frac{5}{2}\cdot 26 = \boxed{65}$.